I know it is not real ale, but there is a real cider festival at the East 
Anglian Railway Museum, Chappel & Wakes Colne nr Colchester (Same location 
as the Chappel Beer Festival) this weekend, Thur eve to Sunday Lunch time. 
About 30 ciders and 2 Real Ales on offer.

Easy rail access, as the "One" Railway Chappel & Wakes Colne station is 
immediately alongside (30 second stagger away)